1. Field of the Invention
The present invention is directed to a decompression circuit. The decompression circuit operates to decompress and/or decode a plurality of differently encoded input signals. The embodiment chosen for description hereinafter relates to the decoding of a plurality of encoded picture standards. More specifically, this embodiment relates to the decoding of any one of the well-known compression standards as Joint Photographic Expert Group (JPEG), Motion Picture Experts Group (MPEG), and H.261.
According to the invention, a plurality of prediction filter circuits may process video information, and a control signal allows processing of video information encoded in multiple standards. A filter circuit as may be used to process video information is disclosed comprising a prediction filter formatter, a dimension buffer, and two one-dimensional prediction filters. Each such one-dimensional prediction filter may comprise six registers, two multiplexers, and two summing circuits, connected together such that processing of video information encoded in multiple standards may be processed.
2. Description of the Background Art
U.S. Pat. No. 4,866,510 to Goodfellow et al discloses a differential pulse code arrangement which reduces the bit rate of a composite color video signal. The reduction is achieved by predicting the present video signal sample from reconstructed past samples and forming a signal representative of the prediction error. The bit rate is further reduced by generating a signal predictive of the error signal and forming a signal corresponding to the difference between the error signal and the signal predictive thereof. On output, a video signal sample is reconstructed by summing the reconstructed error signal and the signal predictive of the previous video signal sample. A video signal sample generally comprises one or more lines of the composite signal.
U.S. Pat. No. 5,301,040 to Hoshi et al discloses an apparatus for encoding data by transforming image data to a frequency zone. The apparatus may comprise two encoding means, which may perform encoding in parallel.
U.S. Pat. No. 5,301,242 to Gonzales et al discloses an apparatus and method for encoding a video picture. The apparatus and method convert groups of blocks of digital video signals into compressible groups of blocks of digital video signals, according to the MPEG standard only.
U.S. Pat. No. 4,142,205 to linuma discloses an interframe encoder for a composite color television signal. The interframe encoder obtains a frame difference signal by subtracting one frame signal from the subsequent frame signal. A corresponding interframe decoder operates in reverse.
U.S. Pat. No. 4,924,298 to Kitamura discloses a method and apparatus for predictive coding of a digital signal obtained from an analog color video signal. During the predictive coding process, a picture element in a first scanning line is predicted on the basis of a picture element in a second scanning line adjacent to the first scanning line.
U.S. Pat. No. 4,924,308 to Feuchtwanger discloses a bandwidth reduction system for television signals. The system employs three spatial filter circuits capable of imposing respective resolution characteristics on the signals. Based on the degrees of motion occurring in respective spatial portions of the television picture, different levels of resolution are imposed by the different spatial filter circuits.
U.S. Pat. No. 5,086,489 to Shimura discloses a method for compressing image signals. According to the patent, original image signals components representing an image are sampled such that the phases of the samples along a line are phase shifted from the samples located along a neighboring line. These representative image signal components are classified into main components, sampled at appropriate sampling intervals, and interpolated components, subjected to interpolation prediction encoding processing based on the main components.